Workplace, an internal communications platform launched Monday by Facebook, is shown on a laptop computer. It is ad-free and separate from users' existing Facebook accounts. Businesses have to pay, but Facebook is offering it to schools and nonprofits for free.

Despite already having more than 1.7 billion users worldwide, Facebook has its sights set on expanding even further. The social networking giant publicly launched a separate ad-free platform Monday designed to simplify on-the-job communication and collaboration.

The subscription product, called Workplace by Facebook, introduces the company into a crowded market for enterprise software and places it in direct competition with Slack, a messaging app introduced three years ago.

Many of the more than 1,000 businesses and organizations that have been testing Workplace during the past year showered praise on the product. Jim Daniell, chief operating officer of the nonprofit Oxfam America, says its familiar user interface has been particularly helpful.

"So from an Oxfam perspective, what was really exciting about this was the idea of taking a tool set that was already familiar to people," Mr. Daniell tells The Christian Science Monitor in a phone interview. After testing a customized platform with about 2,000 employees, Oxfam plans to expand the service to at least 8,000 of its 10,000 employees within 18 months, Daniell says.

Some companies that participated in the pilot said it helped to break down rigid hierarchical relationships of the past.

"We are a bottom-up culture and we need a communications platform that can facilitate that," Gillian Tans, chief executive officer of Booking.com based in The Netherlands, told USA Today. With an average age of 30, her company's 13,000 employees found the Workplace product successful.

Richelle Luther, chief human resources officer for Columbia Sportswear Co., said the platform has sparked new and needed conversation.

For global organizations like Oxfam, which has workers addressing poverty in 90 countries worldwide, Workplace has had perhaps the most important impact by breeding familiarity among coworkers who might not otherwise meet, Daniell says.

"You're very isolated and highly specialized in your job, so it's less breaking down the silos – although that's definitely part of it – and more like feeling part of a tighter, smaller world," Daniell tells the Monitor. "It's like feeling your colleague is just down at the end of a digital corridor. They're right there, and you can see them."

That familiarity could have a downside, of course, as San Francisco-based tech professional Anna Wiener wrote for The New Yorker.

"Productivity software that wants to be your friend is confusing: Are we here to hang out, or to do business?" she wrote, acknowledging that there is some potential power in having 1.7 billion people self-trained on Facebook's standard platform who can readily shift to the Workplace version.

"But, just as there are plenty of reasons to think twice about, say, showering at work, or taking a yoga class with your manager on your lunch break, there are reasons to feel nervous about being too much oneself in corporate-run online spaces, and not just because plenty can go awry when sending emojis to the person who determines your salary," Ms. Wiener wrote.

Christine Moorman, a professor at the Duke University Fuqua School of Business, acknowledged that organizations that take part in the new service may need to clearly communicate their expectations to employees and the public alike.

"They'll probably have to reassure their customers that there will be something that keeps people from just dealing with their personal stuff at work," Professor Moorman told The Wall Street Journal. To combat the impression that Facebook is a distraction, Workplace does not require users to log in from their personal accounts, and it limits what employees see in their news feeds.

Facebook plans to charge $3 per active user for the first 1,000 employees, plus $2 per person for the next 9,000, and $1 for each after that. That's cheaper than Slack's paid version which starts at $6.67 per user.

But there are more than two competitors in this corner of the market. Most of the major corporate software vendors – including Microsoft, VMware, Salesforce, International Business Machines, and Oracle – offer social-networking platforms of their own.

Even so, Facebook is optimistic that its service will prove revolutionary.

"We want to replace a lot of old technologies like internal emails, mailing lists, newsletters," Julien Codorniou, Workplace's global head, told Reuters. "These are things that people want to get rid of."

Even if the sales pitch is too optimistic, Workplace is poised to significantly shape internal communications moving forward, Daniell says. Some messages work well on Facebook while others deserve more formal treatment.

"It's not the end of email, for sure, but it's going to change the nature of email," Daniell says, declaring an end to "those really annoying reply-all" chains.

Although the biggest markets for Workplace include the United States and Britain, emerging markets in Africa and Asia are being targeted as well. Thus far, the biggest market is in India.